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The kinetics of the hydrolysis of 3′-carboxypyridino- s -triazine reactive dyes were studied at 60–130°C in a neutral medium using HPLC. A series of hydrolysis rate constants were obtained and the effects of pH and temperature on the reaction were evaluated. It was found that pH is a key factor at low temperature, but that when the temperature was raised, temperature becomes the more important influence on the hydrolysis. The reactivities of the monochloro- and 3′-carboxypyridino- s -triazine dyes were compared and the results showed that the hydrolysis rate constants of the latter were two grades higher than those of the former. The dyeing properties were also examined and it was demonstrated that the most favourable pH value for dyeing at high temperature is 8; the neutral medium employed in commercial processes is thus not necessarily the optimum condition.

An investigation has been carried out on the reaction kinetics of monochlorotriazine dye with DABCO and nicotinic acid. The results indicate that in a neutral medium and at high temperature the quaternisation of monochlorotriazlne dyes with DABCO takes place more quickly than it does with nicotinic acid. It was found that DABCO is the more active catalyst under the experimental conditions adopted.

A 350-and a 460-fold one step purification of alkaline phosphatase from a crude calf intestine extract has been achived using two new synthesized colourless biomimetic compounds coupled to Agarose CL-4B.

Four new symmetrical colourless biomimetics bearing two monochlorotriazine rings have been rationally designed and synthesized. These immobilized colourless ligands and one analogue of Cibacron Blue F3GA on Sepharose CL-4B were used to purify alcohol dehydrogenase from baker's yeast extract. Twenty-two-fold purification with 78% enzyme recovery was achieved in a single step with specific elution of NAD+ (5 mM) from the colourless absorbent comprised of two ortho-aminobenzene sulphonates as terminal rings, which is comparable to the result obtained from the analogue of Cibacron Blue F3GA. Differential spectra between ligand–enzyme complexes and free ligands were studied. © 1997 John Wiley & Sons, Ltd.

Three series of dyes have been prepared by coupling diazonium salts to 2-thioethyl- and 2-thio-n-butyl-4,6-diaminopyrimidine and to 3-cyano-1,4-dimethyl-6-hydroxy-2-pyridone. Infrared spectra and visible absorption spectroscopic behaviour indicate that the arylazopyrimidines exist in the azo tautomeric form, whereas the pyridone dyes exist as hydrazones. The light absorption properties of the yellow to orange arylazopyrimidines are well accounted for by PPP-MO calculations, although when substituents are present in the aryl ring ortho to the azo group, steric effects cause poorer agreement between theoretical and experimental λ max values. The colour properties of the bright yellow pyridone dyes can also be predicted well by PPP-MO theory. These dyes have higher molar absorption coefficients than the arylazopyrimidines, but this is due to their narrower absorption bands rather than to intrinsically higher absorption intensities.